Hmm. I think his main writings are so straightforward and of reasonable length that I’d recommend those instead. State and Rev, What Is To Be Done, Imperialism: The Highest State of Capitalism, and of course this essay, Left-Wing Communism: An Infantile Disorder.

He was indeed highly insightful, particularly as someone who led an organized revolution. I think some of the best theory building one can do is to use these experiences and insights as a template that you then criticize and update based on salient differences between modern + local conditions and those of Tsarist Russia, Humiliated China, and Colonial Cuba.